Device for shearing tissue

ABSTRACT

A device for shearing tissue in a human or animal body may include a first member made of a first material and a second member made of a second material. A thread is connected to the first member and to the second member, and the first and second materials show magnetic attraction between one another. A means is provided for pulling the thread between the first and second members.

FIELD

The present disclosure is related to assemblies and methods for creatingpressure necrosis of wall portions of internal cavities of a human oranimal body, and possibly creating compression anastomosis of adjacentwall portions.

BACKGROUND ART

There exist a number of medical conditions in which a wall of aninternal body cavity pouches out to form an undesired hollow protrusion,referred to as diverticulum. Diverticulum can occur in various bodycavities, such as though not limited to the gastrointestinal tract(esophagus, intestine, colon), the bladder and the heart. In someinstances of diverticulum, fluids or solid substances such as foodpresent in the cavity can get trapped in the pouch (diverticulum) andremain stagnant for a prolonged period, eventually leading to infection.In other instances, fluid or solid substances get blocked, and cannotpursue their natural course. Current treatment techniques involveendoscopic stapling of the diverticulum. In other medical conditions,there is a need to open or adapt a septum between two cavities.

On the other hand, methods and apparatuses for creating compressionanastomosis between walls of adjacent body cavities and related pressurenecrosis are known from EP 0754434 to Cook Incorporated, 22 Jan. 1997and WO 2012/007052 to Ethicon Endo-Surgery Inc., 19 Jan. 2012. Magnetsare placed in each of the two body cavities, which attract one anotherand attract adjacent cavity walls being interposed between the magnets.The magnets will strongly compress the wall tissues trapped between themleading to a cut-off from blood supply, which causes necrosis of thetissue between the magnets and anastomosis of the surrounding tissue.

From U.S. Pat. No. 8,828,032 to GI Windows Inc., 9 Sep. 2014, it isknown to provide a train of self-assembling magnets which yield a largersurface on self-assembly than the size of any single magnet component.These structures are useful when a larger opening must be createdbetween adjacent body cavities. The train of self-assembling magnets canbe delivered successively through a needle. The magnets may be preloadedwith a suture allowing the proximal and distal magnet elements to betied to one another. The suture continues to run from the needle as theneedle is retracted through the separating wall between the cavities andis attached to the second train of magnets, thereby linking theself-assembly magnet structures in both cavities through the separatingwall. One drawback of the above self-assembling magnet trains is thatthe number of components increases with an increase in the size of theopening that one wishes to create, and therefore the difficulty ofassembling such large number of components increases proportionally.

It is therefore desirable to provide a method and an assembly or devicewhich allow for creating a lesion between adjacent cavities with a samedifficulty level of implementation irrespective of the size of thelesion one wishes to create. It is desirable to provide such methods andassemblies which overcome the above drawbacks. It is desirable toprovide such methods and devices allowing for effectively forming anopening through a tissue wall, in particular tissue walls separatingadjacent bodily cavities and lumens, in particular through pressurenecrosis and/or anastomosis. It is desirable to provide such methods anddevices allowing for creating a lesion, such as tissue shearing, withless trauma, and less complexity. It is desirable to provide suchmethods and devices allowing for effectively treating diverticulumand/or for effectively and easily performing anastomosis, in particularalong or within the gastrointestinal tract.

SUMMARY

Some aspects described further herein therefore provide a device orassembly as set out in the appended claims. The device or assemblycomprises a first member comprising a first material, a second membercomprising a second material and a thread connected to the first memberand to the second member. The first and second materials show magneticattraction between one another. The device or assembly enables toperform methods as described herein. In some aspects described herein,the device of assembly comprises means for pulling the thread. The meansfor pulling the thread is advantageously configured to apply a tensionon the thread between the first member and the second member.Advantageously, the means for pulling the thread is configured to reducea length of the thread between the first member and the second member.

When the thread of the above devices or assemblies are operating withinthe human or animal bodies to shear tissue, the means for pulling thethread allow for applying an additional force/pressure on the tissue bythe thread, so that tissue becomes necrotic due to prolonged action ofthe pressure and can be sheared more effectively, and with increasedsafety, e.g. reducing risk of infections.

According to a first aspect, one or both of the first member and thesecond member are each attached to the thread at a fixed position alongthe thread.

According to a second aspect, at least one of the first and secondmembers are connected to the thread so as to be able to slide along thethread. By way of example, the device or assembly comprises a thirdmember connected to the thread at one end thereof. The first member canbe attached to the other end of the thread. The third member can performas the means for pulling the thread, e.g. it can comprise a massconfigured to pull the thread by gravity.

According to a third aspect, the third member is interposed between thefirst member and the second member. Advantageously, the third membercomprises a material showing magnetic attraction to one or both of thefirst member and the second member. Alternatively, or in addition, aplurality of third members are connected to the thread at spaced apartintervals from one another between the first member and the secondmember. The plurality of third members advantageously show magneticattraction to one or both of the first member and the second member, sothat they progressively pull the thread towards the first or secondmember as the tissue is being sheared.

According to a fourth aspect, the device or assembly comprises a threadwinding system (traction system) configured to pull the thread in orderto maintain a tension on the thread between the first member and thesecond member.

The first to fourth aspects, and any aspects described further hereincan be combined in any suitable combination to provide improved effects.By way of example, the fourth aspect is an implementation example of thesecond aspect as described above.

Some aspects described further herein therefore aim to provide a methodfor shearing tissue by means of the devices and assemblies describedherein. Tissue shearing can be provided alone or in combination withother operations, such as though not limited to pressure necrosis andcompression anastomosis. In one aspect, a method is described forcreating pressure necrosis of a tissue wall between a pouch and anadjacent cavity in a human or animal body, and possibly anastomosis ofsurrounding tissue. The pouch advantageously opens into the cavity. Thetissue wall hence comprises a periphery forming an edge of the openingbetween the pouch and the cavity. These conditions can refer todiverticulum, such as though not limited to Zenker's diverticulum, andepiphrenic diverticulum and present methods advantageously allow fortreating these.

According to the method, a first member is placed into the pouch, suchthat the first member is adjacent the tissue wall. A second member isplaced in the cavity and proximate the first member. The first memberand the second member comprise materials which magnetically attract oneanother. The first member and the second member are placed such thatthere is magnetic attraction between the first member and the secondmember through the wall. Due to the magnetic attraction force, the firstmember and the second member compress a portion of the wall overlappingthe first member and the second member for a prolonged time period,which creates pressure necrosis of that overlapping wall portion. Athread extends between the first member and the second member and isconnected thereto, and extends over the edge to form a loop over thewall.

The tissue compressed between the first member and the second memberbecomes necrotic, and collapses, thereby forming an opening through thewall. Advantageously, due to the means for pulling the thread, acontinuing pressure can be applied by the thread on the tissue, tocreate a local necrosis of the tissue, which aids in tissue shearing bythe thread, and renders it more effective and safer. The first memberand the second member, which remain attached to one another due to themagnetic attraction force, separate from the tissue wall and becomesuspended from the thread. The first and second members and the threadform a closed loop around the tissue wall, enclosing a portion of tissuebetween the edge and the freshly formed necrotic opening. Due to theirweight, the first and second members now may further pull on the threadloop, such as in the direction of gravity. As the thread is supported bythe tissue edge, the tension in the thread caused by the weight of thefirst and second members may further assist shearing the tissue from theedge to the necrotic opening. As a result, the separating wall betweenthe pouch and the cavity can be opened substantially over the entireheight of the wall without having recourse to large magnets or largemagnet assemblies. As a further result, the pouch is now completely opento the cavity, which may prevent infections due to stagnancy in thepouch or create a preferential passage for liquid and solid substances,e.g. through the GI tract. It will be convenient to note that thetension in the thread by the means for pulling the thread on the onehand and by gravity due to the suspended masses of the first and secondmembers on the other hand, may act simultaneously to provide improvedeffects.

Some aspects described further herein aim to provide a method ofcreating compression anastomosis and/or pressure necrosis between one ormore adjacent tissues. Each of the tissues forms a wall of one ofadjacent cavities of a human or animal body. These cavities can e.g.form part of the gastrointestinal tract. Possible anastomosisapplications include, but are not limited to gastrojejunal anastomosisand jejuno-jejunal anastomosis. According to the method, a first memberand a second member are placed in a first one of the adjacent cavities,proximate a first one of the walls, e.g. through an endoscopic deliverydevice guided to the cavity. The first member and the second member arespaced apart and connected to a first thread. A third member and afourth member are placed in a second one of the adjacent cavities andproximate a second one of the walls. The third member and the fourthmember are connected to a second thread and are placed in correspondenceof a respective one of the first member and the second member. Thefirst, second, third and fourth members comprise materials whichmagnetically attract one another through the adjacent tissues to createpressure necrosis of an overlapping portion of the wall.

Due to pressure necrosis, portions of the adjacent tissues overlappingthe first member and overlapping the second member will collapse, andform necrotic openings through the tissues. The tissues adjacent thenecrotic openings will anastomose. The magnetic members fall through thenecrotic opening and remain suspended by the threads, which now form aloop with the first to fourth members. The loop of threads and magneticmembers are supported by the tissue portions between the necroticopenings. The members will pull on the thread due to their weight andstart shearing the tissue portions until a lesion extending between thetwo necrotic openings is formed. As a result, a large opening can becreated between adjacent body cavities in a simple way.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the invention will now be described in more detail withreference to the appended drawings, which are illustrative andnon-limiting, and wherein same reference numerals illustrate samefeatures.

FIG. 1 illustrates a device or assembly for creating pressure necrosisof a tissue interposed between opposing magnets followed by shearing ofthe tissue by a thread.

FIG. 2A represents a cross section of a lumen of the gastrointestinal(GI) tract of a human body along a sagittal plane and illustratesinitial placement of the device of FIG. 1 in performing pressurenecrosis and tissue shearing between the lumen and an adjacent pouch.

FIG. 2B illustrates an opening through the wall separating the pouchfrom the lumen and which is formed by pressure necrosis.

FIG. 2C illustrates further shearing of the separating wall by thethread.

FIG. 3A illustrates the situation in FIG. 2C in a first of two otherviews; specifically a perspective cut-out view of the lumen of the GItract.

FIG. 3B illustrates the situation in FIG. 2C in a second of two otherviews; specifically a view of the hollow parts of the lumen and theadjacent pouch as seen from section plane B-B′ in a downwards directionas indicated by the arrows of FIG. 3A.

FIG. 4 illustrates another application of the device of FIG. 1 forcreating an opening between two adjacent cavities.

FIG. 5 illustrates a device or assembly for creating pressure necrosisin an application as shown in FIG. 4, comprising three magnetic membersconnected to a thread.

FIG. 6A illustrates a first of four different views of a possiblehousing of a member of the device or assembly of FIG. 1 or FIG. 5;specifically a top view of the housing.

FIG. 6B illustrates a second of four different views of a possiblehousing of a member of the device or assembly of FIG. 1 or FIG. 5;specifically a side view taken along a first perpendicular direction.

FIG. 6C illustrates a third of four different views of a possiblehousing of a member of the device or assembly of FIG. 1 or FIG. 5;specifically a side view taken along a second perpendicular direction.

FIG. 6D illustrates a fourth of four different views of a possiblehousing of a member of the device or assembly of FIG. 1 or FIG. 5;specifically a perspective view of the housing.

FIG. 7A illustrates a top view, front view, and side view of themagnetic members of devices or assemblies of FIG. 1 or FIG. 5 having afirst of four different orientations for the engagement hole;specifically the engagement hole arranged centrally and extendingparallel to the surface of contact.

FIG. 7B illustrates a top view, front view, and side view of themagnetic members of devices or assemblies of FIG. 1 or FIG. 5 having asecond of four different orientations for the engagement hole;specifically the engagement hole arranged eccentric and extendingparallel to the surface of contact.

FIG. 7C illustrates a top view, front view, and side view of themagnetic members of devices or assemblies of FIG. 1 or FIG. 5 having athird of four different orientations for the engagement hole;specifically the central engagement hole extending perpendicular to thesurface of contact with ring-shaped magnet surrounding the engagementhole.

FIG. 7D illustrates a top view, front view, and side view of themagnetic members of devices or assemblies of FIG. 1 or FIG. 5 having afourth of four different orientations for the engagement hole;specifically the engagement hole extending perpendicular to the surfaceof contact and arranged eccentric to the magnet.

FIG. 8A illustrates a front view and a corresponding bottom view of afirst of seven different shapes of the surface of contact and housing ofthe magnetic members of the device of FIG. 1 or FIG. 5; specifically aplanar surface of contact.

FIG. 8B illustrates a front view and a corresponding bottom view of asecond of seven different shapes of the surface of contact and housingof the magnetic members of the device of FIG. 1 or FIG. 5; specificallya concave surface of contact.

FIG. 8C illustrates a front view and a corresponding bottom view of athird of seven different shapes of the surface of contact and housing ofthe magnetic members of the device of FIG. 1 or FIG. 5; specifically aplanar surface of contact with protruding edge.

FIG. 8D illustrates a front view and a corresponding bottom view of afourth of seven different shapes of the surface of contact and housingof the magnetic members of the device of FIG. 1 or FIG. 5; specificallya convex surface of contact.

FIG. 8E illustrates a front view and a corresponding bottom view of afifth of seven different shapes of the surface of contact and housing ofthe magnetic members of the device of FIG. 1 or FIG. 5; specifically aplanar surface of contact with intermediate protrusion.

FIG. 8F illustrates a front view and a corresponding bottom view of asixth of seven different shapes of the surface of contact and housing ofthe magnetic members of the device of FIG. 1 or FIG. 5; specifically aplanar surface of contact substantially larger than the size of themagnet.

FIG. 8G illustrates a front view and a corresponding bottom view of aseventh of seven different shapes of the surface of contact and housingof the magnetic members of the device of FIG. 1 or FIG. 5; specificallya stair stepped surface of contact.

FIG. 9A illustrates a top view, front view, and corresponding side viewof a first of three magnetic members of devices or assemblies of FIG. 1or FIG. 5 having different arrangements of magnets; specifically amonolithic magnet of disc or cylindrical shape.

FIG. 9B illustrates a top view, front view, and corresponding side viewof a second of three magnetic members of devices or assemblies of FIG. 1or FIG. 5 having different arrangements of magnets; specifically anarray of multiple disc shaped magnets.

FIG. 9C illustrates a top view, front view, and corresponding side viewof a third of three magnetic members of devices or assemblies of FIG. 1or FIG. 5 having different arrangements of magnets; specificallymultiple magnets arranged in an undefined configuration.

FIG. 10 illustrates an alternative embodiment of a device or assemblyfor pressure necrosis, in which tissue shearing is allowed to occursimultaneously with creating pressure necrosis.

FIG. 11A illustrates a first of two alternative embodiments of thedevice of FIG. 10, which comprise a traction system (thread windingsystem) for loading the thread between the two members in order tomaintain tension in the thread; specifically an embodiment in which thetraction system is a spiral spring and magnets are placed around thespiral spring.

FIG. 11B illustrates a second of two alternative embodiments of thedevice of FIG. 10, which comprise a traction system (thread windingsystem) for loading the thread between the two members in order tomaintain tension in the thread; specifically an alternative for thesecond member, wherein the spiral spring is coiled around a centrallyplaced magnet.

FIG. 12A illustrates a first of three views of an alternative embodimentof the devices of FIGS. 11A-B, wherein the magnet is arrangeddifferently; specifically FIG. 12A represents a perspective view of thedevice.

FIG. 12B illustrates a second of three views of an alternativeembodiment of the devices of FIGS. 11A-B, wherein the magnet is arrangeddifferently; specifically FIG. 12B represents a cross sectional view ofthe second member, and shows the annular magnet and the thread windingsystem including a pulley for winding the thread.

FIG. 12C illustrates a third of three views of an alternative embodimentof the devices of FIGS. 11A-B, wherein the magnet is arrangeddifferently; specifically FIG. 12C represents a perspective partialcut-out view of the second member, and shows the annular magnet and thethread winding system including a pulley for winding the thread.

FIG. 13 illustrates another embodiment of device with an alternativemeans for pulling the thread towards the first and/or second member.

FIG. 14 illustrates an alternative to FIG. 4, in which a through passageis provided in two opposed magnetic members, in order to allow passageof a medical tool, such as a needle through the tissue.

It will be convenient to note that some parts in the figures have beendrawn in transparency in order to uncover interior components.

DETAILED DESCRIPTION

Referring to FIG. 1, a device 10 for pressure necrosis and tissueshearing according to one aspect comprises a first member 11 and asecond member 12 connected to one another by a thread 13. Each of thefirst member 11 and second member 12 can comprise a generally domeshaped housing 110 advantageously made of a biocompatible material. Thehousing 110 encapsulates a material 111, 121 respectively. The materials111, 121 encapsulated within the respective members 11, 12 show magneticattraction to one another. Advantageously, both materials 111 and 121can be permanent magnets. Alternatively, one material can be a permanentmagnet, and the other one a material which is magnetically attracted tothe permanent magnet, such as though not limited to a ferromagneticmaterial, e.g. an iron alloy. Each of the first member 11 and the secondmember comprises a generally planar surface of contact 112, 122respectively, advantageously forming a bottom of the housing 110. Thematerials 111 and 121 advantageously have magnetic properties such thatthey show magnetic attraction when the first member and the secondmember are placed with their surface of contact 112, 122 against eachother, e.g. through suitable orientation of the magnetic poles N and Sof the permanent magnets within the housing 110. In use, therefore, thefirst and second members will be disposed in such a manner that thesurfaces of contact 112, 122 are in facing relationship. Each of thefirst and second member further comprises a point of attachment 113 atwhich the thread 13 is connected to the respective member. The threadconnection at 113 is advantageously a fixed connection, e.g. the thread13 is fixedly secured, such as through tying or potting to the member.Each member 11, 12 may further comprise a suitable structure forfacilitating handling of the member, e.g. an eye 114, allowing anendoscopic tool for engaging the respective member.

As a surprising effect, the device 10 allows for creating an openingthrough a tissue wall separating two body cavities. The opening islarger than the size of any of the first member 11 and the second member12. To this end, the members 11, 12 comprising the magnets 111, 121 areused, in a first step, for compressing tissue between oppositelyarranged magnetically attracting members thereby causing pressurenecrosis. Subsequently, in a second step, the necrotic tissue collapsesand forms an opening. The members 11, 12 lack support by the tissue andwill fall through the opening created by necrosis. The members 11, 12become suspended by thread 13 and will pull on the thread 13 due togravity. The thread 13, supported by the tissue, will start shearing thetissue to create a larger opening.

A first possible application is shown in FIGS. 2A-C and relates totreatment of diverticulum, such as though not limited to Zenker'sdiverticulum, which is a pouch 21 protruding from a lumen of the GItract 20. In the particular case of Zenker's diverticulum, the lumen 20is the hypopharynx. Referring to FIG. 2A, the device 10 is introducedinto the lumen 20 and the first member 11 placed in the pouch 21 whilethe second member 12 placed in the lumen 20 at a corresponding location.The device 10 can be introduced by any suitable endoscopic means. Sincethe pouch 21 is open towards the lumen 20, a delivery device, such as anendoscope with suitable system for engaging and positioning the members11, 12, e.g. a grasper, forceps or specific catheter, can be guided tothe pouch 21 to place the first member 11. No tissue needs to be piercedin order to place member 11. The same endoscope or another endoscope canbe guided to the adjacent lumen 20 to place the second member 12. It isalternatively possible to place the second member 12 first, and to placethe first member 11 subsequently. The thread 13 is either connected tothe two members 11 and 12 prior to loading the device 10 in theendoscope, or may be connected to either or both members upon placement.Advantageously, the thread 13 connecting the two members 11 and 12 doesnot pass through the tissue wall 23, but forms a loop over the periphery24 of the tissue wall. The placement of the members can be guided withendoscopic ultrasound and/or fluoroscopy which are procedures well-knownto persons skilled in the art of endoscopic procedures.

Referring to FIG. 2B, due to the magnetic attraction between the members11 and 12, the tissue wall 23 gets trapped between the two members andis compressed. By suitable selection of the magnetic attraction forcebetween the magnets 111 and 121, a compression pressure larger than 5 mmHg can be created, which is sufficient for stopping blood supply to thetrapped tissue and hence causing necrosis of the tissue within a fewdays. The necrotic tissue trapped between the members 11 and 12collapses and frees the members 11 and 12 which remain attached to oneanother and suspended on the thread 13. The first and second members andthe thread now form a closed loop around the tissue wall 23, enclosingthat portion of tissue interposed between the periphery 24 and thefreshly formed necrotic opening. Due to their weight, the members 11 and12 now pull on the thread loop 13 in the direction of gravity. Referringto FIG. 2C, the thread 13 is now supported by the periphery 24 of thetissue wall and the tension in the thread 13 caused by the weight of themembers 11 and 12 will start shearing the tissue from the periphery 24until the initial opening 22 formed by necrosis is reached. The actionof the thread 13 shearing the tissue wall 23 is represented in FIGS.3A-B from other viewing directions. By so doing, a lesion extending overthe entire depth of the pouch 21 can be created without requiringrecourse to larger structures and without requiring specific deliverydevices.

The example described above is just one possibility of how device 10 canbe used. Referring to FIG. 4, with two such devices 10 and 10′, witheach one device placed in one of two adjacent cavities 40, 41, a lesioncan be created extending over the distance by which the first member 11and the second member 12 are spaced apart. The magnetically attractingmembers 11 and 12′ of respective devices 10, 10′ are placed incorrespondence, each in the respective cavity. Portions of the tissuewalls 42 and 43 of each respective cavity 40, 41 overlapping the members11 and 12′ are compressed. Likewise, the other members 12 and 11′, whichalso magnetically attract each other, are placed in correspondence, eachin the respective cavity at a location spaced apart from the members 11and 12′. Portions of the tissue walls 42 and 43 overlapping the members12 and 11′ are compressed. Members 11 and 12 are spaced apart from eachother, such as by a distance of at least 40 mm, advantageously at least50 mm to enable making a larger lesion. The tissue trapped betweenmembers 11 and 12′ on the one hand and between members 12 and 11′ on theother hand will become necrotic and collapse, which will free themembers towards one cavity 40 or the other one 41. Either thread 13 or13′ will be pulled by the freed member couples 11-12′ and 12-11′ in thedirection of gravity, which will shear the tissue in between theopenings formed. It will be convenient to note that also in the case ofFIG. 4, no puncture or piercing through the tissue wall is required forinitial placement of the devices 10 and 10′, as long as both cavities 40and 41 are accessible. A configuration as in FIG. 4 may be useful forcreating gastrojejunal anastomosis or jejuno-jejunal anastomosis.

It will be convenient to note that devices and assemblies describedherein advantageously allow to perform tissue shearing assisted bypressure necrosis and/or compression anastomosis.

Even though the devices 10 and 10′ in FIG. 4 are shown to comprise twomagnetic members 11, 12 and 11′, 12′ each, it will be clear that deviceconfigurations comprising more than two members, such as three membersor four members connected by a thread are similarly applicable. By wayof example, device 50 shown in FIG. 5 comprises three members 11, 12 and14 connected by thread 13. Two such devices 50 can be used in the sameway as the example shown in FIG. 4, each device being placed in adifferent one of the adjacent cavities 40 and 41, as with the devices 10and 10′. The third member 14 may comprise its proper magnet 141 ormagnetically active material.

The shape of the housing 110 of the members 11, 12 and possibly 14, andthe shape of the magnets or magnetically active materials 111, 121 aswell as of the surface of contact 112, 122 is not particularly limited.Suitable shapes and configurations may be chosen depending on anyparticular application. By way of example, instead of dome-shaped, suchhousing may be cylindrical, advantageously with planar top and bottombase. There is no preference for using the top or the bottom as surfaceof contact in the latter case.

Each member can comprise a suitable handling structure for manipulatingthe member. In a first example, referring to FIG. 5, the members 11, 12and 14 can comprise one or more thread loops 117 which facilitatehandling of the members by a forceps. The thread loops 117 project fromthe housing of the member and can be provided in addition or inalternative to other handling structures, such as the engagement eye. Inanother example, referring to FIGS. 6A-D, the engagement eye or hole114, or the thread loop 117 as in FIG. 5, can be replaced by, or besupplemented with an advantageously ribbed projecting wall 115 allowingengagement by a forceps, e.g. of the types commonly used in endoscopicprocedures. The magnet, or magnetically active material is received ininterior and completely closed recess 116. Referring to FIGS. 7A-D, theengagement hole 114 may be oriented parallel to the surface of contact112, perpendicular thereto, or oblique.

Referring to FIG. 7C, it may be useful to provide the hole 114 as athrough-hole and the magnet 111 advantageously surrounding thethrough-hole 114. The through-hole is advantageously arranged totraverse the surface of contact 112 of the member. One advantage of suchan arrangement is shown in FIG. 14. FIG. 14 differs with respect to FIG.4 only in the shape of the second members 12, 12′ which comprise such athrough-hole 114 and in which the magnets are advantageously annularsurrounding the through-hole 114. Referring to FIG. 14, the through-hole114 allows to pass a medical tool, such as a needle, through therespective member 12, 12′. Since the magnets of members 12 and 12′surround the through-hole 114, a necrotic tissue, which may beanastomosed, is created surrounding the location of the through-hole114, allowing a needle or other tool to pass through the tissues 42 and43 safely.

Referring to FIGS. 8A-G, the surface of contact 112, 122 which definesthe contact being made between the member and the tissue, can be, butneed not be, planar. Other kinds of shapes, such as concave, convex,stepped or staircase-like can be contemplated. It will be convenient tonote that the surface of contact of members placed at opposite sides ofthe tissue wall, such as members 11 and 12 in FIG. 2, and members 11 and11′ in FIG. 4, may have a complementary shape. By way of example, theshapes shown in FIGS. 8C, 8E and 8G may be complementary. In anotherexample, two mushroom-shaped members as shown in FIG. 8G may be used.These mushroom-shaped members may form plugs or anchors preventing themagnetically attached members to fall through the tissues once thetissue becomes necrotic and collapses.

Referring to FIGS. 7A-D and FIGS. 9A-C, the magnets 111, 121 or, as thecase may be, magnetically active materials can have any suitable shape.They may be monolithic within the housing 110, or made up of separateparts arranged adjacent one another, as shown in FIGS. 9B-C. Othershapes than disc or cylindrical are possible, such as ring, oval orparallelepiped.

It will be convenient to note that the shearing by the thread 13 can befacilitated by suitable selection of the mass (weight) of any of themembers 11 and 12. Generally, a tension on the thread of at least 5 mmHg may be sufficient for causing tissue shearing, with tensions of atleast 10 mm Hg, at least 20 mm Hg, at least 50 mm Hg, or at least 100 mmHg being advantageous. In some instances, it may be useful to maintainthe thread 13 under a constant tension, as from the onset, particularlyeven prior to the collapse of the tissue due to pressure necrosisperformed by the members 11 and 12. One possible way of accomplishing isby making one of the members slidable relative to the thread. Referringto FIG. 10, device 60 differs from device 10 in that the second member62 is not fixedly attached to the thread 13, but is allowed to slidealong the thread. The first member 11 is attached to one end of thethread 13, and a mass member 63 is attached to the opposite end ofthread 13, with the second member 62 being slidingly attached to thread13 in between the first member 11 and the mass member 63. To this end,the second member 62 comprises a through hole 621 slidingly receivingthread 13. Mass member 63 has a suitable weight in order to provide adesired tension in thread 13, but will advantageously not bemagnetically attracted to either one of the members 62 and 11. Inparticular, mass member 63 may not comprise any magnet or magneticallyactive material. Mass member may have a mass at least equal to 50%, 75%or 100% of the mass of any one of the members 11 and 12. When members 11and 62 are placed as shown in FIG. 2, the mass member 63 is freelysuspended and will pull on the thread 13 and put it under tension toimmediately start shearing tissue. It will therefore be clear thatdevice 60 allows for simultaneous pressure necrosis and tissue shearing.A yet alternative embodiment is obtained by adapting the arrangement 10of FIG. 1 to include the mass member 63 interposed between the firstmember 11 and the second member 12. In this case, mass member 63 may,but need not be slidingly attached to the thread 13.

FIG. 11A-B show alternative embodiments to the device 60, in whichtension in the thread 13 is created through a thread winding systemintegrated within one of the members, or both. Referring to FIG. 11A,device 70 differs from device 10 in that the second member 72 comprisesa thread winding system 74 for loading thread 13 in order to maintaintension in the thread. Thread winding system 74 can comprise a spiralspring 741 which is preloaded to pull on thread 13 according to adesired preload force acting in the direction of the arrow. Magnets 71may be placed peripherally to thread winding system 74, as shown in FIG.11A, or in any other suitable configuration. Referring to FIG. 11B, analternative to FIG. 11A is shown, which differs from device 70 in thatthe thread winding system 75 in the second member 73 is a spiral springwhich is coiled around magnet 76, i.e., spring 73 and magnet 76 areconcentric. In an alternative embodiment, the arrangement of FIG. 10 isadapted to incorporate the thread winding system in the mass member 63.

Yet an alternative embodiment to the devices 70 of FIGS. 11A-B is shownin FIGS. 12A-C, representing a device 80 comprising a thread windingsystem 84 incorporated in the second member 82. Device 80 differs fromdevice 70 in the disposition of magnet 81 (see FIG. 12B) which isannular and arranged above or below the thread winding system 84.Alternatively, possibly annular magnets may be arranged above and belowthe thread winding system, e.g. in a symmetrical fashion. The threadwinding system 84 comprises a spiral spring operably connected to apulley 86. Thread 13 is wound on pulley 86. Spiral spring 85, or anyother suitable spring, is advantageously preloaded to apply a suitabletorque on pulley 86 to pull on thread 13. In the latter design, thethread winding system 84 and the magnet 81 can be kept separated fromone another without interference.

Referring to FIG. 120; a blocking system 89 can be provided in thesecond member 82 for blocking rotation of the thread winding system 84.By way of example, blocking system 89 comprises a blocking member 88which blocks the pulley 86 and/or the spiral spring 85, e.g. byengagement. The blocking system 89 is releasable, e.g. by pulling onthread 87 attached to blocking member 88, the blocking member 88 isreleased and the pulley and spiral spring can turn and wind the thread13.

Referring to FIG. 13, a yet alternative embodiment is shown, whichdiffers from device 10 in that a plurality of third members 91 areattached along the thread 13, between the first member 11 and the secondmember 12. The third members may be arranged with advantageously uniformspacing between one another and they are advantageously fixed to thread13. The third members advantageously show magnetic attraction to thefirst member 11 and/or the second member 12 and act here as threadpulling means. As the tissue is further sheared, the third member 91closest to the first member 11 will progressively move to the firstmember due to the magnetic attraction. The third members 91 can have anysuitable shape, e.g. beads, and advantageously have dimensionssubstantially smaller than those of the first member and second member,e.g. half or less of the size of the first member and/or second member.It will be convenient to note that neither the thread winding system inFIGS. 11A-B and 12A-C, nor the third members in FIG. 13 prejudice theposition and shape of the magnet or magnetically active material, of thehousing, or of the surface of contact, and these features may assume anysuitable shape, e.g. as illustrated in FIGS. 7A-D through 9A-C.

Yet another alternative to the systems shown in FIG. 10 through 13 is touse an elastic or resilient thread to couple the members to one another.This thread is advantageously preloaded prior to placement of thedevice, e.g. by providing an appropriate structure which maintains themembers at a distance larger than the length of the thread at rest,which structure is removed upon installing the device. The thread isstretched and thereby preloaded. In one example, the thread may be madeof, or comprise a shape memory material. Suitable shape memory materialsare shape memory polymers or (metal) alloys, which e.g. can retract at abody temperature level. One example is DiAPLEX® commercialised byMitsubishi Corporation Fashion Co., Ltd., Japan. The use of a massmember pulling on the thread, of a traction system, or of elastic orresilient thread can be advantageously used in the application referredto in FIG. 4. That is, either one or both the devices 10 and 10′ in FIG.4 may be provided with means for (pre)loading the thread 13, 13′. In theexample of FIG. 4, (pre)loading the threads 13, 13′ with tensile stressenhances fusion between the tissues 42 and 43.

The thread is advantageously made of a non-resorbable material, and isadvantageously a monofilament thread, e.g. made of polyamide. The shapeof the housing 110 is advantageously atraumatic. While in the aboveembodiments, only one thread is described extending between the firstmember and the second member, it will be convenient to note that aplurality of such threads, e.g. two, three or more can be provided toextend between, and be connected to the first member and second member.The means for pulling the thread may be operable to pull some or all ofthese threads. Multiple threads advantageously allow for shearing tissueacross multiple, spaced apart sections.

Each of the members has a diameter D (see FIG. 6B) or largest sizeadvantageously smaller than or equal to 40 mm, advantageously smallerthan or equal to 30 mm, advantageously smaller than or equal to 20 mm,advantageously smaller than or equal to 15 mm, advantageously smallerthan or equal to 20 mm. The member 11 or 12 can have a diameter or sizeof at least 5 mm, advantageously at least 10 mm. The thread 13 extendingbetween the members has a length which in an initial placement positionis advantageously at least 80 mm, advantageously at least 100 mm,advantageously at least 120 mm. The mass of the member 11 or 12generally depends on the application, and may be determined on the basisof e.g. contact length of the thread with the tissue in order to arriveat a desired tension on the thread.

Some aspects of the present invention as described herein are set out inthe following numbered clauses.

A. Method of creating pressure necrosis of a tissue wall between a pouchand an adjacent cavity in a human or animal body, wherein the tissuewall comprises a periphery forming an edge of an opening between thepouch and the cavity, the method comprising:

-   -   placing a first member into the pouch, such that the first        member is adjacent the wall,    -   placing a second member in the cavity and proximate the first        member,    -   wherein the first member and the second member comprise        materials which magnetically attract one another,    -   wherein the first member and the second member are placed such        that there is magnetic attraction between the first member and        the second member through the wall and wherein the first member        and the second member compress an overlapping portion of the        wall to create pressure necrosis,    -   wherein the first member and the second member are connected        through a thread, wherein the thread extends over the edge.

B. Method of clause A, wherein, following pressure necrosis, the firstmember and the second member are suspended by the thread forming a loopover the wall.

C. Method of clause B, wherein the thread shears the wall by action of aweight of the first and second members.

D. Method of clause B, wherein the thread shears the wall while thethread is under tension by action of a mechanism that induces a tractionforce in the thread.

E. Method of clause B, comprising exerting a pulling force on the threadwhile the thread shears the wall.

F. Method of clause B, wherein the wall is cut by the thread in adirection of gravity.

G. Method of clause A, wherein the thread does not pierce through thewall until pressure necrosis is created.

H. Method of clause A, wherein at least one of the first member and thesecond member comprises an encapsulated magnet.

I. Method of clause A, comprising inserting a delivery device having aninternal lumen into the cavity, and

-   -   guiding the delivery device through the opening to the pouch and        delivering the first member to the pouch by sliding the first        member through the internal lumen;    -   delivering the second member to the cavity by sliding the second        member through the internal lumen;    -   wherein the first member and the second member are connected by        the thread in the internal lumen.

J. Method of clause A for treating diverticulum, wherein the pouch is adiverticulum.

K. Method of clause J, wherein the cavity is a segment of agastrointestinal tract of the human or animal body.

L. Method of creating compression anastomosis between adjacent tissues,each of the tissues forming a wall of one of adjacent cavities of ahuman or animal body, the method comprising:

-   -   placing a first member and a second member in a first one of the        adjacent cavities, proximate a first one of the walls, wherein        the first member and the second member are spaced apart and        connected to a first thread;    -   placing a third member and a fourth member in a second one of        the adjacent cavities and proximate a second one of the walls,        wherein the third member and the fourth member are connected to        a second thread and are placed in correspondence of a respective        one of the first member and the second member;    -   wherein the first, second, third and fourth members comprise        materials which magnetically attract one another through the        adjacent tissues to create pressure necrosis of an overlapping        portion of the wall.

M. Method of clause L, wherein the first thread does not extend to thesecond one of the adjacent cavities upon placement of the first andsecond members and wherein the second thread does not extend to thefirst one of the adjacent cavities upon placement of the third andfourth members.

N. Method of clause L, comprising a step of shearing the adjacenttissues by the first thread or the second thread, wherein the shearingopens a lesion extending between a necrotic opening through the adjacenttissues formed at a location of the first member and a necrotic openingthrough the adjacent tissues formed at a location of the second member.

O. Method of clause N, wherein one of the first thread and the secondthread shears the adjacent tissues while the respective thread is undertension by action of a mechanism that induces a traction force in therespective thread.

1-16. (canceled)
 17. A device for shearing tissue in a human or animalbody, the device comprising: a first member comprising a first materialand a first surface of contact; a second member comprising a secondmaterial and a second surface of contact; wherein the first and secondmaterials show magnetic attraction between one another when the firstand second surfaces of contact are disposed in a facing relationship;and a thread connected to the first member and to the second member;wherein the device comprises means for pulling the thread configured toreduce a length of the thread between the first member and the secondmember, wherein the means for pulling the thread comprises a threadwinding system configured to maintain tension in the thread between thefirst member and the second member, and wherein one or both of the firstmember and the second member comprises a housing enclosing the threadwinding system.
 18. The device of claim 17, wherein the means forpulling the thread is configured to apply a constant tension on thethread between the first member and the second member.
 19. The device ofclaim 17, wherein the first member and the second member are configuredto be attached to each other, such that the first and second members andthe thread form a closed loop.
 20. The device of claim 17, wherein themeans for pulling the thread comprises a plurality of third membersconnected to the thread at spaced apart intervals from one anotherbetween the first member and the second member, wherein the plurality ofthird members show magnetic attraction to one or both of the firstmember and the second member.
 21. The device of claim 17, wherein thethread winding system comprises a spring which is preloaded such thatthe spring is configured to pull the thread.
 22. The device of claim 21,wherein the spring is a spiral spring.
 23. The device of claim 17,wherein the first member and the second member each have a diametersmaller than or equal to 30 mm, and wherein the thread extending betweenthe first member and the second member has a length of at least 100 mm.24. The device of claim 17, wherein the first member, the second member,or both the first member and the second member comprise a second threadattached to a housing of the respective member, the second threadforming a loop exterior to the housing.
 25. The device of claim 17,wherein the thread is elastic, and wherein the means for pulling thethread comprise a releasable preload structure for preloading thethread.
 26. The device of claim 17, wherein the thread comprises a shapememory material.
 27. The device of claim 17, wherein at least one of thefirst member and the second member comprises a through-hole, and whereinthe respective first or second material surrounds the through-hole. 28.A device for shearing tissue in a human or animal body, the devicecomprising: a first member comprising a first material and a firstsurface of contact; a second member comprising a second material and asecond surface of contact; wherein the first and second materials showmagnetic attraction between one another when the first and secondsurfaces of contact are disposed in a facing relationship; and a threadconnected to the first member and to the second member; wherein thedevice comprises means for pulling the thread configured to reduce alength of the thread between the first member and the second member,wherein the means for pulling the thread comprises a third memberconnected to the thread, wherein the second member is slidinglyconnected to the thread, and the second member is interposed between thefirst member and the third member along the thread.
 29. The device ofclaim 28, wherein the third member comprises a mass configured to pullthe thread by gravity.
 30. The device of claim 28, wherein the means forpulling the thread comprises a thread winding system configured totension the thread between the first member and the second member. 31.The device of claim 30, wherein the thread winding system comprises aspring which is preloaded such that the spring is configured to pull thethread.
 32. The device of claim 31, wherein the spring is a spiralspring.